Some conventional semi-submersible vessels have pontoons that have sharp edges (1) and corners (2) (see FIG. 1). Sharp edges or corners of the pontoons will induce strong flow separation and reverse flow (lower pressure) zone (3). The low pressure zone may remarkably increase the current drag on the pontoons in transit state.
The reverse flow (4), indicated by the shaded areas in FIG. 2, under the bow of a pontoon structure will affect the performance of thrusters which may experience fluctuating incoming flow while rotating.
Therefore, it is desirable to provide a pontoon structure with improved designs that seeks to address at least some of the problems encountered in conventional pontoon structure and/or at least to provide an alternative.